In this study, a high resolution version of the Cambridge p-TOMCAT chemical
transport model is used, along with measurement data from the 2008
NERC-funded Oxidant and Particle Photochemical Processes (OP3) project, to
examine the potential impact of the expansion of oil palm in Borneo on
atmospheric composition. Several model emission scenarios are run for the
OP3 measurement period, incorporating emissions from both global datasets
and local flux measurements. Using the OP3 observed isoprene fluxes and OH
recycling chemistry in p-TOMCAT substantially improves the comparison
between modelled and observed isoprene and OH concentrations relative to
using MEGAN isoprene emissions without OH recycling. However, a similar
improvement was also achieved without using HO<sub>x</sub> recycling, by fixing
boundary layer isoprene concentrations over Borneo to follow the OP3
observations. An extreme hypothetical future scenario, in which all of
Borneo is converted to oil palm plantation, assessed the sensitivity of the
model to changes in isoprene and NO<sub>x</sub> emissions associated with land-use
change. This scenario suggested a 70% upper limit on surface ozone
increases resulting from land-use change on Borneo, excluding the impact of
future changes in emissions elsewhere. Although the largest changes in this
scenario occurred directly over Borneo, the model also calculated notable
regional changes of O<sub>3</sub>, OH and other species downwind of Borneo and in
the free troposphere.